Air seeders and other seeding devices are commonly towed by tractors to apply seed or fertilizer, or both simultaneously, to a field. As an example, an air seeder may be towed in combination with a tilling implement, one behind the other, to place the seed and fertilizer under the surface of the soil. An air seeder has as its central component a wheeled seed cart which comprises one or more frame-mounted product tanks for holding product, generally seed or fertilizer or both. Air seeders also generally comprise a metering system for dispensing product from the tanks and a pneumatic distribution system for delivering the product from tank to soil.
It is known to provide an air seeder with volumetric meters which measure a fixed volume of seed per unit of linear distance. These volumetric meters typically comprise either augers or fluted cylinders (meter rollers) which rotate through a product reservoir to measure granular product, as illustrated in U.S. Pat. Nos. 3,489,321 and 3,763,797. The meters rotate to feed product into a pneumatic distribution system. The pneumatic distribution system of an air seeder generally utilizes a centrifugal fan to provide at least one airstream which flows through the pneumatic distribution system to seed boots where product is deposited in the soil. Product is first introduced to the air stream by the metering system at a primary distribution manifold located below the metering system. Product is carried by the air stream through distribution lines to a series of secondary distribution manifolds ("headers"), which in turn distribute product through distribution lines to seed boots mounted behind ground openers on the tilling implement so that the product may be evenly delivered to the span of ground (the "tillage") acted upon by the tilling implement.
Operators of conventional seeding equipment have problems configuring distribution manifolds for accepting metered product from multiple tanks entering into the pneumatic distribution systems. When an operator wants to switch tank applications or the setup of the tilling implement, the operator must reconfigure downstream distribution lines to ensure that product is applied in the proper location on the tillage.
In addition, if the operator wishes to inspect, repair, or replace components of a primary distribution manifold, the operator must remove bolts or other fastening devices used to mount the primary distribution manifold on the seed cart.
Also, conventional primary distribution manifolds do not foster optimal product flow as product enters the ports of the primary distribution manifold, often resulting in damage to the product and disjointed delivery of product to the tillage.
Therefore, it is desirable to devise a primary distribution manifold having a means for the operator to adapt the pneumatic distribution system for varying configurations of other components of the seed cart and the tilling implement. It is also desirable to devise such a manifold which promotes a smooth flow of metered product.